The principle objective is to determine the neural circuitry of the vertebrate retina. By means of light microscopy of Golgi-impregnated cells it is possible to study the overall morphology of the neurons and correllate these findings with serial section electron microscopy and reconstructions of neurons. We can thus determine the morphology and synaptic circuitry of input and output of the individual neurons of the retina. In cat rod and cone pathways remain segregated at the outer and inner plexiform layers and finally converge onto common ganglion cells. The rod pathway uses internuncial amacrines to get information from bipolar-ganglion cell. Cone bipolars, however, segregate their input to two systems of ganglion cells, determined by stratification of bipolar endings and ganglion cell dendrites. It is hoped to correlate these anatomical findings with the single cell physiology in order to determine how the retina processes visual information.